Process for preparing tris[3-(alkoxysilyl)propyl] isocyanurates
The present invention relates to a process for preparing a tris[3-(alkoxysilyl)propyl] isocyanurate from the group of tris-[3-(trialkoxysilyl)propyl] isocyanurate, tris[3-(alkyldialkoxysilyl)propyl] isocyanurate and tris[3-(dialkylalkoxysilyl)propyl] isocyanurate by hydrosilylation, by in step A initially charging a mixture comprising at least one hydroalkoxysilane from the group of hydrotrialkoxysilane, hydroalkyldialkoxysilane, hydrodialkylalkoxysilane [called H-silane(s) for short], at least one carboxylic acid and a Pt catalyst, heating the mixture to a temperature of 50 to 140° C., in step B adding a mixture of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and at least one alcohol to the mixture from step A while mixing, in step C leaving the mixture from step B to react while mixing and in step D working up the product mixture thus obtained.
1. A process for preparing at least one tris[3-(alkoxysilyl)propyl] isocyanurate selected from the group consisting of tris[3-(trialkoxysilyl)propyl] isocyanurate, tris[3-(alkyldialkoxysilyl)propyl] isocyanurate and tris[3-(dialkylalkoxysilyl)propyl] isocyanurate by hydrosilylation, the process comprising:
(A) initially charging a mixture comprising at least one H-silane selected from the group consisting of hydrotrialkoxysilane, hydroalkyldialkoxysilane, and hydrodialkylalkoxysilane, with at least one carboxylic acid and a Pt catalyst, and heating the mixture to a temperature of 50 to 140° C.,
(B) adding a mixture of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and at least one alcohol to the mixture obtained in (A) while mixing,
(C) leaving the mixture obtained in (B) to react while mixing and
(D) working up the product mixture thus obtained.
2. The process according to claim 1 , wherein a molar ratio of the at least one H-silane relative to alcohol is 1:0.005 to 0.3.
3. The process according to claim 1 , wherein a molar ratio of the at least one H-silane relative to Pt is 1:1×10 −4 to 1×10 −9 .
4. The process according to claim 1 , wherein a molar ratio of the at least one H-silane relative to carboxylic acid is 1:1×10 −3 to 30×10 −3 .
5. The process according to claim 1 , wherein a molar ratio of the at least one H-silane relative to olefin component is 1:0.1 to 1.
6. The process according to claim 1 , wherein the carboxylic acid is at least one selected from the group consisting of benzoic acid, propionic acid, 2,2-dimethylpropionic acid, 3,5-di-tert-butylbenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, and acetic acid.
7. The process according to claim 1 , wherein the alcohol is at least one selected from the group consisting of C1-C10 alcohols.
8. The process according to claim 1 , wherein the at least one H-silane is at least one selected from the group consisting of hydrotrimethoxysilane (TMOS), hydrotriethoxysilane (TEOS), methyldiethoxysilane (DEMS), methyldimethoxysilane (DMMS), dimethylethoxysilane (DMES) and dimethylmethoxysilane (MDMS).
9. The process according to claim 1 , wherein the Pt catalyst is at least one catalyst selected from the group consisting of a Karstedt catalyst, hexachloroplatinum(IV) acid, and Pt applied to a solid catalyst support.
10. The process according to claim 1 , wherein the alcohol is at least one selected from the group consisting of tert-butanol, ethanol, methanol, benzyl alcohol and diglycol monomethyl ether.
11. The process according to claim 1 , wherein the Pt catalyst is a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in the form of a Karstedt catalyst in xylene or toluene with a Pt(0) content of 0.5% to 5% by weight, hexachloroplatinum(IV) acid dissolved in acetone, or Pt supported on activated carbon.
12. The process according to claim 1 , wherein the Pt catalyst is a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in the form of a Karstedt catalyst in xylene or toluene with a Pt(0) content of 0.5% to 5% by weight.
13. The process according to claim 1 , wherein the process does not comprise a separate addition of an aliphatic or aromatic hydrocarbon as solvent or diluent.
14. The process according to claim 1 , wherein at least 90 mol % of allyl groups in the 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione are converted by hydrosilylation to 3-(alkoxysilyl)propyl groups.
15. The process according to claim 1 , further comprising:
separating the Pt catalyst from the product mixture obtained in (C) prior to (D) working up the product mixture, thereby obtaining a separated Pt catalyst, and
recycling the separated Pt catalyst.
16. The process according to claim 1 , wherein (D) working up the product mixture comprises distillation at a temperature of from 45° C. to 150° C. at a pressure of less than 1 bar, thereby removing at least one selected from the group consisting of carboxylic acid, alcohol, H-silane, and olefin.
17. The process according to claim 1 , wherein said at least one tris[3-(alkoxysilyl)propyl] isocyanurate is tris[3-(trialkoxysilyl)propyl] isocyanurate.
18. The process according to claim 1 , wherein said tris[3-(trialkoxysilyl)propyl] isocyanurate is tris[3-(trimethoxysilyl)propyl] isocyanurate.
19. The process according to claim 1 , wherein said tris[3-(trialkoxysilyl)propyl] isocyanurate is tris[3-(triethoxysilyl)propyl] isocyanurate.